Speakek otit



LWLSW- Feb. 5, 1929.

L. E. BALTZLEY SPEAKER UNIT 3 Sheets-Sheet v 1 Filed Ma 20, 1926 a E EIEEI "MEI INVENTOR 9 3 1 3, a m e m m m .L m MN RN w F 5 1v ilk Y W ,2 w n RN m T w. il 2 m m A E. Y |U! B m m \M Q R a RN Qmm W 69w wmw E W MW Na. l I l lr fi L l n o u i am 2 v V v MN QM dfi j w i E V Z 1 Feb. 5, 1929.

' theiido'pt l atented Feb. 5, 1929.

LOUIS E. BALTZLEY, OF GLEN RIDGE, NEE

SPEAKER UNIT.

Application filed May 20, 1826. Serial No. 110,318.

Special objects ofthe present invention are to provide an actuating unit for sound reproducers of the loud speaker type, which,

will reproduce faithfullywithout distortion, the. low pitch, the hi h pitch and the interm'edietetones throughout the scale oi? nudihilit which will he suiiiciently sensitive to re oduoe the or lighter as well as the heavier, more dominantsounds; w ich will operate direct and without the losses which occ 1' when a system of linkage connections ployed; which will be powerful in action; and capable oi producing the desired sound volume and. which, furthermore,will be of relatively simple construction, consisting of but comperntiveljv few purts, readily essemhled and adjusted and suited to monu- 'IYiCtlll'G on a large scale The foregoing und other desirehle objects are attained in this invention by certain novel features of construction, comhinutions and relations of parts hereinafter fully described and broadly claimed. v

The drawings accompanying and forming part of th s specification illustrate certain practical embodiments and uses of the invention. As these illustrations are prime.- riiy for purposes'of disclosure, it should he understood that the SLHCtLU'Q may be modified and its mode of use be altered in various without dcnurture from the true spirit and scope ofthe invention RS herein defined =1; view 0i" :1 spculcei. unit of the invention.

tudinul sectional view 1 .ie 2-2 of Figure 1.

, sectional view of the ntinlly the plane of line 3 2;

o. detached perspective view .J p, 1w 1W1 lo-dole oo o piece) ant l giuo a is u view ole modification.

l .re 5 1s an enlarged sectional View .e resilient urinatui mounting, omewlnit '1 s ,netther in.

its resilient mounting; strip. cross sectional view i e f-the unit-with d is per sectionslview showing .tlon of the invention the horn type.

e s "d to illustrate theyection ot the his a broken 'ilnnview of the toe speaker of Figures 9-l0 are blOliGIl ClQflil views of a modification in which the armature is at-' tached only to the intermediate portion oi" t-he supporting strip and has only a simple to and fro movement with respect to the magnct. l

gures are'similar views illustrating z modification in which the magnet system polarized to produce it loci-Zing movement of the urnuatiu-e.

Fi ures 13 and 14 are side and end sectional views of a modified form of strip tensioning means. 7

Figure 15 is 1 cross sectional view illustrating embodiment of the invention in a structure oi the bi-poler magnet type.

The pernuuient por ion of the nuignet system is shown in the illustration as consisting of single fairly heavy horse shoe or lJ-shupo magnet 10. T flux of this mugis concentrated controlled to efiect our-way push-pull action on the armature I" so dicae in Figure 5 so that-like pole tips stand diagonally opposite on diiierentsides of an intermediate plane and with unlike poles immediately opposite on dili'ercnt sides of the same plane. This urrsngement of polar tips is effected n the illustration by making each pole piece indi i e with hs nntiull;

i s .125, l; cmiuected inteun iinermedizile r. :igg'ouul. hruue l5 rehing one side downwardly us oi polar pijection to e ole below the urn'iui. re level and the oihei upwardly nrr y the, other 11 tip to a po" on shove the armature plane.

These pole pie es are shown arranged irimsversely ot t e ends of the U mugne, projecting inwai y toimrd each other and 'ith their polar tips in ogtiposition, being secured in this position with the lower edges of the sfC portions resting on top of the n'iog'n'et and held so h square washers 18 hearing on the upper edges of the side portions. said woshers being secured by bolts 11m, down through openings 20 in and through the arms {I il'llliO the supporting base 21.

A 0 bolts thus serve ooth to secure the-magnet on the hose and the pole pieces in the cone type and at same.

' and pole pieces are faced off so that the act of assembling these parts serves to automatically position them in proper relation.

The gaps between the pole tips of opposite polarity are alined to provice a narrow operating space for the armature, which is shown as a thin flat bar or strip 22 of suitable magnetic material. Directly connected with this armature is a power applying rod or stylus 23 by which the vibrations are imparted to the sound wave creating member, which latter is shown at 24 in Figure 7 as of 25 in Figure 8 as of the diaphragm type acting;' in conjunction with a born 26.

A special feature of the present invention is the manner in which the arn'iature is inoiiiined in the magnetic iield. This inounting is shown as a narrow thin strip or ribbon 27 or strong elastic material such as phosphor bronze stretched taut between two end supports or abutinents and having the arn'iature fixedly secured on the bridging portion thereof. The supports for this strip are illustrated as fret blocks 28, 29 secured by screws 30, 31 on the reversely inclined seats 32, 33 ot' the base, said screws passing also through the strip to anchor he same. Screws 3%, 35 extending upwardly through the base, bear on the inner or upwardly tilted end portions of the fret blocks and serve as a means for tilting these blocks to position the supporting strip and the armature carried thereby centrally in both of the magnetic gaps.

For tensioning the supporting strip an ad justing screw 36 is provided in Figures 1 and 2 acting on a cross bar 37 which pressesa bight in the strip into a cross cavity 38 in the fret block 29.

i A convenient and practical method of mounting the armature on-the flexible supporting strip is illustrated in detail in Figures 5 and (3, where the strip is shown 'lorined with a relatively wide slot 39 in the region oi the magnet poles and a connnunicatingr narrower slot 40 extending therelron'i substantially to the adjacent fret block 28, the armature bar being shown as of a width to pass it'reely into the wider portion of? the slot and as being grooved in. the sides thereof at 4-1 to slide into the narrow *r portion of the sot over the edges bounding the sides of the Once thus positioned the armature may be secured in the desired relation by soldering or otherwise, as indicated at The actuating coil is shown a single winding 43 carried by a hollow spool 4a and this spool is shown as positioned between the cheeks 16, 17 of the polar projections against properly located positioning lugs 45 on the inner faces ot'such cheeks. To fasten'the coil thus located, screws 46 may be utilized to draw the checks of each pair together and thus clamp the. spool fixedly therebetween.

From Figure '2 it will be apparent that by proper adjustment of anchorage screws 30, 31 and fret block adjusting screws 34:, 35, the supporting strip may be raised or lowered at one or both ends to center the armature in both the magnetic gaps and that by means oi screw 36 the tension of the supporting strip may be increased or decreased tosecure the desired or best action I in the reproducer. T his tension adjustment has the efiect OI" controlling the tone or pitch or the speaker intruiiient. By increasing the stress the pitch raised and conversely by reducing the tenthe natural pitch is lowered. Similar and practically corresponding ei'i'ects may be attained by increasing or decreasing the weight 01 the arn'iat-ure or by Varying the th Thus, de-

armature clement.

tui 1e ei'l'ee t of raising the pitch while i r he weight or 1e ethening the arv J mature lowers the pitch. Because of these possibilities the units may be manufactured justed to suit dillerent tonal qualities CleolrQCl. I

By reducing the tension, the unit may be made more susceptible to faint signals, but ordinarily the tension should be kept sui"li cient to prevent the armature from COillllCLll'lg the pole tips. Any tendency to contact the )ole tips can be overcome by increasing the tension or by adjusting the fret screws to. restore the armature to central position in the gaps. V

The armature has the effect of making rigid that portion of the strip to which it is fixedly secured; namely, that partineluded by the bracket A in Figures 5 and 6.

The balance of the armature, that part included by bracket 13, is free of the strip and so can in ove independfntly of the strip. This stmctural relation enables the supporting; strip to hinge on the line substantially at the edge of the fret 28, the balance of the lil'li) from the beginning oi the Wide slot at 4:8 to the other iret 29 being free to y .a" the action of the map; et. This condition is enc er Led in l igure 5 where the free end of the e iure illustrated as having swung about the jl uler in point i? to a point where its "free end ofiiset or out of line with the supporting strip. The moveinent o'f the free end oi? the armature being greater than that of the intermediate portion oithe armature. the gap turthest ren'iorcd from fulcrum 47 may be slightly wider than the nearer gap, as shown in Figure 5. These gaps should be small, consistent with the need of keeping the armature from contacting with the pole pieces and the ability to place any. required tension on the supporting strip makes it possible to keep the gaps at a minimum.

l iqure 5 shows how the four way push-pull nia ;netie eilcct is obtained. The-pole tips of e weight orslmrtening the arma-i siinilz r polarity are diagonally opposite, with whichevcrway the armature is temporarily magnetized by the coil, there will be combined attraction and repulsion at both ends of the coil, all acting on the armature in the same direction so that a powerful efect is obtained in a slight range of movement. This is the efiect desired for the operation of cone speakers and the like. The wide slot in the supporting strip increases the flexibility and sensitivity of this support, enabling the armature to respond to relatively feeble signals, even when the strip is heavily tensioned.

The resilient mounting and supporting of the armature at both ends and the direct rigid attachmentof'r' the stylus rod to this bodily movable armature make it possible to entirely support he cone or airvil rating member from the unit. For the purpose, a stiff stylus rod connection 23 may be employed. In some cases it may be desirable to brace or guide the outer end of the stylus rod and to relieve it of any whipping tendency by extending it through a hearing; such as shown at i9, in Figure '7, which may be in the form of a sleeve lined with felt or the like.

In the modification illustrated in Figure 9, the armature is attached to the supporting strip at a point substantially midlength the coil and the movement is taken. from this attached central portion. In this structure the slot in the supporting strip is widened at both ends as at 39 and the intermediate portion'of the slot is restricted for a short distance as shown at 40. The restricted portion being; located appronnnately within the center or the coil, it follows that the armature will be I held to the st ip only at the center or" the coil and will be free of the strip at both ends so that the, strip can bow more or less without twisting the armature and the armature there fore can have a straight bodily to and fro movement with respect to the magnet poles. The stylusrod is connected with this centrally attached portion and extends out thro l n opening provided in the coil or between 'dili'erentsections ot the coil. This construchas the advantage of imparting ght pnsl The modification illustrated in Figure 1 0 is onthe order of that just described, but in this instance the area'ot engagement between the armature supporting strip is of less length, as shown at 40 and the magnet sys tem is polarized to effect a reciting movement of the armature indicated. The stylus rot in this case is connected with end of the armature at a point just outside or inside one of the pole cheeks.

Various m ins; tor the tension of the supporting strip may be employed, one simple practical device for this purpose being illustrated in Figur 9 and ci'insisting of a sliding anchorage block Site which the supporting strip is attached and which has polar projections.

and pull movements to the sound wave y creatin member. may be secured on oi-lied rear ardly extending arms 52 sliding beneath over-sanding shoulders in the abutment 58. A screw 5 L extended through this abut-me 4 and a screw seat in the sliding block serves to position said block and hence enables the supporting strip to be set at any desired tension.

The extent to which the arn'iature supporting strip is tensioncd determines largely the pitch or tonal characteristics oi t e speaker and this stment, therefore, in U conveniently be used as a means for tuning the speakto indivir The stress placed on he strip may amount to one hundred pounds ore. v This amply sutlicient to hold the ti-ally supported in a relatively narrow magnetic gap and to overcome the possibility of the armature contacting the This construcion eliminates the need for any centralizing springs or other accessories and leaves the-armature free to respond entirely to the magnetic forces set a h ghly sensitive o r sponsive condition in the held or the magnetic system.

The various pa ts of the device are of simstructure and such as can readily be tandardized in production. These parts are can be manufactured accurately and quickly assembled in proper relation.

e contributes largely to the ease and asseniblage, being shown as proflat s ats the sides of the same for arms of the U magnet and with bridges or hed portions 56, 5. at the opposite ends torined'to provide the raised inclined seats 82, 83 for the fret blocks. Between these raised seats the base is hollowed at to afford ample clearance for the polar projections and the coils suuported th reheti'a'een. Th t part of the b. i whirb carries the sea t icr outer anchorage blocl: is shown extend.-

clear of the magnet strucarinaturc, therefore is y actically floated in ture and as peri'o ated at 5 for screws or like tastenings 60. F e C l""fi'l1lCl1 the unitport 6]. Tu this let. thecuter end or the as carried by an art; i cured beneath the anchora outer end the supporting The invention is well ads 7 x 1 p-tab. to receiver s of the bi-polar type such as shown in Figure 15, where 63 indicates an ordinary Cinagnet having polar projections 64 carrying coils 65. The flexible supporting strip is tensioned between the end supports 66, 67 and carries the armaturest-rip positioned above themagnet poles. The stylus rod is shown directly connected with the armature strip before described and may be usedas above to actuate a diaphragm, cone or other sound Wave genly raise the strip bodily.

crating device. Instead of using the ordinary cup shaped base such as common in these receivers, the base may be in the form of a spring yoke having projections to enter openings in the ends of the supporting strip so as to impart the desired longitudinal tension to said strip.

Where, as "for instance in i5 igures 1, 5 ant 15, the relatively rigid arn'iature strip is 01 greater length than the polar structure of the magnets, that section which extends beyond the polar structiire may be of nonferrous metal. Thus in the views referred to, the proiectii'ig portion GS of the armature strip may be a section of any suitable nonmagnetic metal welded or otherwise rigidly secured to the magnetic portion of the armatui strip by an end weld or other ri (l joint 69 at a point outside or near the adjacent pole pieces. This concentrates the mag" etic action to those sections of the armature strip which are in the immediate range of the pole tips and prevents stray or waste of the magnetic energy. The armature proper, therefore, may be made just the right length to be most efiicient and the desired action be obtained by using with this armature, a nonferrous extension strip of the length required to give such action.

In the rocking form of armature shown in Figures 11 and 12, it should be noted that the stylus rod 28, instead of being located outside the pole pieces may be located in a space provided therefor inside the adjoining pole piece substantially as indicated in dotted lines in Figure 11.

s The sound wave generating member usually'is so light as to have little or no biasing effecton the armature. When the receiver is positioned vertically as in Figure 7, any sagging tendency due to the weight of the cone nay be offset by the guide for the stylus rod or by adjusting toe supporting strip at one or both ends suiiiciently to compensate for the zufidcd weight and bring the arinatin'e to a normal centrally supported position in the gap when carrying the weight of the cone. When the device is arranged horizon tally as in Figure 9 both ends ot the strip may be adjusted alike, for instance, to slight The cone may be applied to the stylus rod with the apex inward, instead of as shown in Figure 7, such arrangement permitting the use of a shorter stylus rod.

As in the manufacture of the unit on a production scale, it is practically impossible 'to assemble the devices with the pole tips spaced exactly the right distance apart, means may be provided for quickly ellecting this result after the lnirts have been put together. Such means are shown in Figures 1,2 and 4- as small taper screws 1 0 of brass or other non-magnetic material engaged with the companion screw seats 71 formed as extensions on the edges of opposing pole tips and thereby adapted to act as fine wedges for forcing the pole tips apart. In practice, the pole pieces are set up with the pole tips too close together and the separating screws are then entered in the split screw seats until the pole ti s are separated tothe desired extent, which can be easily determined by entering a thickness gage between the tips. The two screws enable each gap to be independently the proper width and the ad justnicnts once made will be retained because ot the binding action of the screws in the screw seats.

in the structure shown in Figure 4, separatin screws 70" are employed, each mounted in a screw seat 71" on the edge of one pole tip and bearing the e ot the opposing pole tip. The ac tion of these screws is the same as described with respect to the wedging sor'm arrangement has the advantage that the screws can be r ched from a position over the top oi? the u it.

in forms of the device such as illus rated in Figure 5, it has been found desirable to extend the magnetstrip, whether it be of the full magnetic or part magnetic construction close to the trot 28 so to locate the hinge 47 at alixed point, substantially at the edge of the fret. That portion of the armature strip which extends from thislulcruni point and is rigidly secured to the supporting strip is in the nature of a lever. It will be apparent that by varying the length of-this lever section, that is, the portion includec. within bracket A, different eliectsmay be obtained. For exa1npl.e,a heavier diapha'rgm or sound wave creating member requires increased longitudinal tension on the supporting strip. This increased tension has a tendency to bind the armature or to carry its natural period too high. This tendency is overcome by sin ply decreasing the rigidly held portion of the armature, that is, the length:

upon an extension lug 72 on This 7 within bracket A until the proper balance is i restored.

l i' ll ll? is claimed is: v 1. In co nation, a base, a U magnet n ounteil ud ha between the arms 0 on the base beyoiui the ends of the magnet, a strip secured in bridging relation between said supports, a armature element carried so, a 8111713011. on the base Elinl bysaid strip, polar projections at the terini= nails of the magnet and positioned to operate the. U magnet, a support" by said strip and polar projectionsat the ter:

on the armature element and an energizing coil carried by said polar projections and surrounding the armature element.

In combination, a base, a L magnet mounted on said base, a support on the base between the arms of the L? magnet, a support on the base beyond the ends of the magnet, a strip secured in bridging relatimrbetween said supports, a armature element carried by said strip,polar projections at the terminals oi the magnet and positioned to operate on the armature element and an impulse transmittin connection )rO'ectin from said 23 i b mounted on said base, a support on the base between the arms of the U magnet, a support on the base beyond the ends of the magnet, a strip secured in bridging relation between said supports, an armature element carried by said strip, polar projections at the terminals oi the magnet and positioned to operate on the armature element, said supports for the armature supporting strip comprising fret blocks and means for variably securing the same on the base.

6. In combination, a permanent U magnet having opposed polar projections at the eX- trei'nit-ies of the same, providing a magnetic gap therebetween, an armature disposed in the gap between said polar projections, a tensioned resilient supporting strip for said armature extending longitudinally between the sides of the U magnet, supports for said strip at opposite sides of the gap and means in conjunctionwith one of said supports for I applying a stretching tension to that portion of the supporting strip extending through th magnetic gap, I

(.In combination, a base having seats at OPPOSi't'G sides of the same and raised por tions at oppos te ends of the same, a U magnet supported on said side seats, a flexible strip tensioned between the raised portions oi the base, an armature carried by saidstrip and polar projections at the ends or" the magnet actively related to the armature.

S. In combination, reversely inclined frets, resilient strip supported in tensioned rela tion on said frets, an armature element carried by strip, amagnet system operatively associated with said armature and means for independently varying the inclination of said ieV rS y incl ned frets tor-the purpose oi variably positioning the opposite cnds of said resilient armature supporting strip.

9. In combination, a permanent U magnet,

pole pieces each comprising substantially parallel side portions connected by a diagonal brace, means for securing said pole pieces with the edges of the side portions bearing on the arms of the permanent magnet, the side port-ions of said pole pieces terminating in opposed polar tips and an armature positioned between the opposed polar tips. 10. In combination, a permanent U magnet, pole pieces each comprising substantially parallel side portions connected by a diagonal brace, means for securing said pole pieces with the edges of the side portions bearing on the arms of the permanent magnet, the side portions of each polepiece having reversely arched extensions terminating in pole tips disposed at opposite sides of a common intermediate plane and an armature interposed between said pole tips in said intermediate plane.

11. In combination, a permanent magnet having pole pieces, each of said pole pieces having unitary spaced parallel side portions connected by intermediate integral braces With oppositely faced polar tips disposed at opposite sides of an intermediate plane and an armature supported in .said intermediate plane.

12. In combination, a permanent magnet having opposed pole pieces, each of said pole pieces having unitary laterally spaced substantially parallel side portions connected by intermediate integral braces and terminating in oppositely faced polar tips of like polarity disposed at opposite sides of an intermediate plane and an armature supported to operate between said pole tips.

13. In combination, a permanent magnet having opposed pole pieces, each or said pole pieces having unitary laterally spaced subsrantially parallel side portions connected by intermediate integral braces and terminating in oppositely faced polar tips of like polarity disposed at opposite sides of an intermediate plane and an armature supported to operate between said pole tips, the polar tips being connected with the main bodies of the portions by deeply arched sections extending away from the intermediate plane.

14. In combination, a flexible strip, sup ports for the opposite ends of said strip, an armature extending longitudinally of said strip and rigidly attached to said strip for a portion of its length and :tree of the strip for the balance of its length and a magnet structure acting on said armature.

15. In combination, a flexible strip, supports for the opposite ends of said strip, an armature extending longitudinally of said strip and rigidly attached to said strip for a portion of its length and free of the stri for n at) the balance of its length and a magnet structure acting on said arniature, said magnet structure including polar projections and a magnetizing coil positioned to operate on the free portion of the armature. v

16. In combination, an armature support-- ing strip having a slot therein, an armature having a portion rigidly secured in one part of said slot and another portion tree to operate in another part 01' said slot, supporting means for said strip and a magnet structure acting on said armature.

17. In combination, an armature supporting strip having a slot therein, an armature having a portion rigidly secured in one part of said slot and another portion tree to operate in another part of? said slot, supporting means for said strip and a magi'iet structure acting on said ari'nature, said magnet structure including polar projections and a magnetizing coil positioned to act upon the tree portion of said armature.

18. In combination, an armature supporting strip having a slot with a portion of re dueed width, an armature element grooved in its opposite edges to fit over the edges boundin the reduced portion of the slot, an impulse transmitting connection associated with said armature and a magnet structure positioned to act on the armature.

19. In combination, spaced supports, alongitudinally tensioned resilient strip bridged between said supports, an armature element fixed on said strip closely adjacent to one of the supports and extending toward the other supportand a magnet structure positioned to act on that portion of the armature projecting away from the support.

20. In combination, an armature supporting strip having a slot therein reduced in Width at a point iutorn'iediate the ends thereof, an armature element. engaged with the edge portions bounding the reduced section of the slot and tree of the edges bounding the Wider end portions of the slot and a magnet structure operating on said armature.

21, In cmnbination, an armature supporting strip having a slot therein reduced. in width at a point intermediate the ends thereof, an armature element engaged with the edge portions bounding the. reduced section of the slot and tree of the edges bounding the wider end portions of the slot and a mag; not structure operating on said armature and including pole pieces polarized to GIIQCt movement oi the armature in the same direction at both ends thereof.

22. In combination, an arn'iature supporting'strip having a slot therein reduced in Width at a point intermediate the ends there of, an armature element engaged with the edge portions bounding the reduced section of the slot and free of the edges bounding the Wider end portions of the slot and a magnet structure operating on said armature and ineluding pole pieces polarized to client reverse movements of the opposite ends of the armature, the attached portion of the armature being disposed intermediate the ends of the same to enable rocking movements of the same.

In combinatioma sound Wave creating member operating in free air, a relatively stationary telephone unit for actuating the same, said unit having a projecting stylus rod connected with the sound Wave creating memher and a guide for said stylus rod at the back of said member, said rod having a freely sliding engagement in said guide so as to be supported in and have its movements directed by said guide. I

2%. In combination, a telephone unit hav ing a projecting stylus rod, a rigid relatively stationary guide for said rod and with which said rod has a tree sliding engagement and sound Wave generating member supported on the port-ion of the stylus rod projecting beyond the guide.

netic portion projecting away from the nonl magnetic portion and a n'iagnet system positioned to act only on the magnetic portion of said armature strip. 7

27. In combination, a magnet system, an armature element consisting of-a magnetic portion located Within the immediate range of action of the magnet system and a nonmagnetic portion projecting beyond the immediate field of the magnet system and a flexible support connected with non-magnetic portion of said armature elen'ient;

In con'ibination, an arn'iaturo supporting strip, an anchorage for one end of t 7 same, a slidably supported block to viithe opposite end o'l said strip is secured, screw means for shifting said block to tension the strip, an armature element carried by the pot on of the strip intermediate end supports and a niagne structure positioned. to act on said armature element 29. In combination, an ill'llil lulfi supporting strip, an anchorage for one end of the X same, a shdably supported block to which the opposite end of said strip is seciu ed, screw means for shifting said block to tension the strip, an armature element carried by the portion of the strip intermediate the end supports, a magnet structure positioned to act on said armature element and a postfor guiding the sliding member, said post and sliding member having slidingly related parts and the screw means being mounted in said post. i r

30. In apparatus of the character disclosed, a longitudinally tcnsioned resilient supportstrip, an armature element carried by said strip. magnet structure having pole pieces to act on said armature element, means for variably position n the oppos e ends of said strip andineans tor varyii'ig ld tensile stress on said armature strip.

31. As an article or" manufacture, a piece for a permanent nu. substantially parallel side nected in spaced relation by an intermediate brace extending diagonally from the edge of one member to'the tar edge of the other member, said members projecting longitudipole gnet comprising nally beyond said brace in oppositely archedextensions ternnnating in oppositely facing polar tips.

32. The con'ibination with a magnet, of a pole piece therefor having substantially pi allel spaced sides connected by a ding-oi brace, said sides extending beyond said brace and terminating in pole tips and means for securing said pole piece to the body or" the magnet.

33. The conibination with a magnet, ot' a pole piece therefor having substantially par allel spaced sides connected by a diagonal brace, said sides ext-ending beyond said brace and terminating in pole tips and means for securing said pole piece to the body 01" the magnet, the polar extensions haying reverse ly arched portions carrying the pole tips and said pole tips being faced in opposite di rections. V

3%. In combination, a magnet structure including opposing pole tips of magnetic material separated by'a narrow magnetic gap,

an armature disposed in said gap, a magnet winding about the gap and armature and non-magnetic means adjustable for forcing said pole tipsapart to vary the width of bent.

svstem 36. In combination wth a magnet and an armature therefor, a l'GSlllQIlt supporting strip for said armature and spaced supports for said strip, one o'tsaic supports being inclined away from the other support and forming a fret over which the strip is bent and means for varying the inclination of said fret to variably position the armature strip accordingly.

members con 37. In combination with a magnet systen'i and an armature therefor, a resilient supporting stip for said armature and spaced supports for said strip, one of said supports being inclined a 'ay from the other support and forming a fret over which the strip is bent, means for the incli: ation of said fret to variably position the armature strip accordingly and means for variably tensioning the armature strip independently of its support on said fret.

In combination, a flexible strip, an armature attached to said strip for a portion of its length and tree of the strip for another portion of its length, a magnet structure having polar projections positioned to operate on the tree portion of said armature and means for variably tensio'ning said strip to control the action of themagnet on the free portion of the armature.

39. In combination, a flexible strip, an armature attached to said strip tor a portion of its length and tree or" the strip for another portion oi its length, a magnet structure having polar projections positioned to operate on the tree portion of said armature, means variably tensioningsaid strip to control the action of the magnet on the tree portion of the armatur and an impulse transmitting member connected with the attached portion (ii the armature.

40. In apparatus of the character disclosed, a longitudinally tensioned resilient supporting strip, an armature element carried by said strip, a magnet structure having pole pieces to act on said armature element, means for variably positioning said strip with r speet to the pole pieces and'means for varying the tensile tension on said armature strip independently ofth'e positioning aforesaid.

ll. In apparatus of the character di closed. the combii ition with a magnet system and an armature actuated thereby, of a tensile tensioned resilient support for said armature, a free edge sound wave creating member carried by said resilient support and means for variably tensioning said support to position said sound member and to place the armature in proper operative relation to the mag net system.

in combination, a tensile tensioned re silicntstrip of non-magnetic material, :1. st rip oi magnetic material fixed to said noumagnetic s rip. an im mlse transmitting connection'extending from said magnetic strip, a magnet structure having polar tips positioned to act on said magnetic strip, means pulse element carried by said tensioned strip, an

from said arn'iature element, a magnet system having two sets of opposed polar projections forming two magnetic gaps in which the armature element is located, said end sup ports being each adjustable to independently position the opposite ends oi the armature element in the respective magnetic gaps and means for independently varying the tensile stress of said supporting strip.

v 44-. In apparatus of the character d s closed, a permanent magnet having opposed pole pieces closely spaced to form a thin but relatively Wide magnetic ga a thin flat r silient strip or appreciable Width extending through said magi etic gap, lre-ts at opposi;e sides of the magnetic gap having supporting edges disoosed toward the gap and on which the supporting strip rests, a thin flat armature element rigidly a] ed to said supporting strip and loca e-:1 in the magnetic gap aforesaid, a magnetwinding surrounding said arn'iatnre element and the (trip carrying the same, an impulse tran-anitting rod connecte'. with said armature element and means for tensile tensioning and for bodily shifting the strip for centering the armature element in the magnetic gap. D

45. In apparatus of the character disclosed, a permanent magnet of the horse-shoe type, a support between t 1e arms oi? said magnet, a support ecatcd beyond the arms of the mag: et, an armature strip secured in bridging relation between said pports, polar proj ections at the ends of the nr net arms posia: tioned at opposite sides of the armature strip, mea is for variably tensile tensioning said armature strip, an electromagnetic Winding associated with the polar projections and an im ulse transmitting connection extending from the armature strip'at a point beyond the arms of the magnet.

it}. 11. apparatus of the character disclosed, a permanent magnet ot the h rse-sho beim'een the arms oil said magne a located beyonr the arms of th 1 net, an armatiiire strip s cured in bridging rehit-ion between said sn 'iports, polar projections at the ends of the magnet arms posttioned at opposite sides t tne armature strip, means for variably tensile tensioning said armature s e, an electroma 'nctie winding i. 1': associated with the pol: r projections, an im transmitting connection extending from the armature strip at a point beyond the arms of the magnet and means for el iecting relative adjustment between the on said armature stri), said tinned to act miniature Eitl'lj being rigidly secured to the Lea-magnetic supporting strip for a portion a its length and free of the supporting strip another portion of its length and arranged ltll said tree portion subjected to the influence of the magnetizing coil.

ill. in apparatus of the character discl wed, a flexible supporting strip, a relatively rigi l arn'iature strip rigidly secured to said supporting strip fo a portion of its length l f cc of the supporting strip for another of its lcngtl and a magnetstructure i; ling polar projections and a magnetizin 1, said coil and polar projections being pcmtioncdto act on the tree portion of said i rmatnre strip.

49. In apparatus of the character disclosed, a man-net system, an armature elementconsisting of a magnetic portion locatel Within the immediate range of action of the magnet system and a non-magnetic portion. projecting beyond the innnediate field of the magnet system, a flexible support connected .vith the non-magnetic portion and free or? the magnetic portion of the armature element and a vilnfltion transn'iitting member connected. with said armature element.

50. In apparatus of the character disclosed, a magnet providedivith pole pieces defining a magnetic gap, an armature ported in said magnetic gap, a magne coil said arn'iatnre, a projecting 'tance them said armature, a {Wide e \i' he dis ant one. portion of said, re-

p it remote from the armature, said he'ng supported independently of the arma- 1 .r o as to be unahect-ed by vibrations of 'ina "are and capable of gun ra r 01 a ind wave generating element thereon irreof, l have hereunto my day oi May, 1926.

LOUlS BALTZLEY,

1g and sns- 

